JPH11219975A - Alignment method of solder ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for aligning solder balls wherein solder balls are put, one by one, in all recessed parts provided on a solder ball alignment plate for easy alignment of the solder balls in a specified array pattern, with no occurrence of flaw or recess with the solder balls. SOLUTION: A lot of solder balls 2 are thrown in a solder ball alignment plate 1 where a lot of recessed parts 5 which, the solder balls 2 which are to be external connection terminals of a semiconductor element housing package being put one by one, comprises suction holes 5a at bottom surfaces, are aligned in a specified array pattern, then, while suction air from the suction holes 5a, the solder ball alignment plate 1 is rocked so that the solder balls 2 are sucked in the recessed parts 5 one by one, after that, an air is blown to the solder ball alignment plate 1 for removing excessive solder balls 2 so that the solder balls 2 are aligned on the solder ball alignment plate 1. Thus, the solder balls 2 are easily aligned in a specified array pattern with no flaw or recess occurred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for arranging solder balls, which serve as external connection terminals of a package for housing semiconductor elements, on a solder ball alignment plate in a predetermined arrangement.

[0002]

2. Description of the Related Art In recent years, a ball grid array (BG) has been used as a package for accommodating semiconductor elements.
A) type semiconductor element storage packages are increasingly used.

In this BGA type semiconductor element housing package, as shown in a sectional view of FIG. 2, for example, a wiring conductor 13 and a bonding wire 14 are provided on the lower surface of an insulating container 12 made of alumina ceramic or the like for housing a semiconductor element 11. A large number of external connection terminals 15 composed of solder balls electrically connected to the electrodes of the semiconductor element 11 through a grid
They are attached in an array of shapes.

In this package for housing a BGA type semiconductor device, after a semiconductor device 11 is housed inside, an external connection terminal 15 composed of a solder ball provided on a lower surface of an insulating container 12 is soldered to a wiring conductor of an external wiring board (not shown). The semiconductor element 11 housed inside by connection by reflow or the like is connected to an external electric circuit, and it is small and high-density surface mounting is possible.

In order to attach a large number of external connection terminals 15 made of solder balls to the lower surface of the insulating container 12 of the package for storing a BGA type semiconductor element, it is necessary to use an insulating container 12.
A large number of connection pads 16 made of, for example, a tungsten metallized metal plated with nickel or gold on the lower surface are provided in a predetermined lattice arrangement so as to be electrically connected to the wiring conductor 13. At the same time, a method is adopted in which the solder balls are aligned and brought into contact with these connection pads 16, which are heated to weld the external connection terminals 15 made of solder balls to the connection pads 16.

At this time, it is extremely troublesome work to individually and individually position solder balls to be the external connection terminals 15 on the connection pads 16 attached to the lower surface of the insulating container 12, respectively. A method is adopted in which all solder balls to be welded to the connection pads 16 are previously aligned in a predetermined lattice-like arrangement, and the aligned solder balls and the connection pads 16 are collectively positioned. I have.

Conventionally, the following method has been adopted as a method for aligning solder balls in a predetermined lattice-like arrangement.

As shown in the sectional view of FIG. 3 and the partially enlarged sectional view of FIG. 3, a large number of recesses 22 capable of accommodating solder balls 21 one by one and having suction holes 22 a on the bottom surface are formed on the top surface. Then, a large number of solder balls 21 are put on the solder ball alignment plate 23 formed in a predetermined lattice arrangement, and then the solder ball alignment plate 23 is swung while sucking air downward from the suction holes 22a. The solder balls 21
How to house and align in 22.

As shown in a sectional view in FIG. 5, a large number of solder balls 31 are placed in a box 32 capable of accommodating a large number of solder balls 31.
A suction head 33 provided with suction holes 33a in a predetermined lattice arrangement is arranged above the box 32, and air is drawn upward from the suction holes 33a of the suction head 33, that is, outside the box 32. By applying vibration to the box 32 while sucking air, or by blowing air into the box 32 from an air outlet (not shown) provided in the box 32.
A method in which the solder balls 31 in 32 are flipped up to reach the suction head 33, and the jumped-up solder balls 31 are sucked into suction holes 33a of the suction head 33 to be aligned.

[0010]

However, in the above method, as shown in FIG. 4, a plurality of solder balls 21 are formed in one recess 22 by suction force from suction holes 22a.
At the same time, these are arranged side by side while keeping a balance with each other, so that they are easily attracted to the recesses 22 so as to cover the recesses 22. As a result, the solder ball alignment plate 23
However, it is difficult to accommodate the solder balls 21 one by one in all the recesses 22 and to arrange them in a predetermined lattice-like arrangement.

In the above-mentioned method, the plurality of solder balls 31 are not simultaneously sucked into one suction hole 33a of the suction head 33 at all. Body 32 and suction head
33 or the solder balls 31 violently collide with each other, so that there is a problem that the solder balls 31 are scratched or dented. Since the solder balls 31 have flaws and dents, when the solder balls 31 are welded by contacting the connection pads provided on the bottom surface of the insulating container of the semiconductor element storage package, the solder balls 31 There is also a problem that air between the connection pad and the connection pad is caught in the welded portion, and as a result, the strength of attachment of the solder ball 31 to the connection pad becomes weak.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to accommodate a single solder ball in every recess provided in a solder ball alignment plate and to form a solder in a predetermined arrangement. An object of the present invention is to provide a method of aligning solder balls that can easily align balls and does not cause scratches or dents in the solder balls.

[0013]

According to the method of arranging solder balls of the present invention, a plurality of solder balls, each of which is capable of accommodating a solder ball to be an external connection terminal of a package for accommodating a semiconductor element, and having a suction hole on a bottom surface, are provided. A large number of the solder balls are put on the solder ball alignment plate in which the concave portions are aligned in a predetermined arrangement, and then the solder ball aligning plate is swung while sucking air from the suction holes to enter the concave portion in the concave portion. Adsorbing the solder balls one by one, and then blowing air on the solder ball alignment plate, removing excess solder balls and aligning the solder balls on the solder ball alignment plate. Is what you do.

According to the solder ball aligning method of the present invention, the solder ball aligning plate is inserted into each of the plurality of concave portions formed in a predetermined arrangement on the solder ball aligning plate while sucking air from the suction holes on the bottom surface of the concave portion. After swinging and adsorbing one or more solder balls, air is blown onto the solder ball alignment plate to remove excess solder balls. Even if the solder balls are sucked simultaneously, the air is blown out, so the suction balance of the plurality of solder balls sucked in one recess is lost, and only one of the solder balls is accommodated in the recess. The Rukoto. Therefore, the solder balls can be easily aligned by accommodating one solder ball at a time in all the recesses provided in the solder ball alignment plate in a predetermined arrangement.

Further, according to the solder ball alignment method of the present invention, the solder balls are aligned by swinging the solder ball alignment plate, so that the solder balls and the solder ball alignment plate or the solder balls are aligned. Does not damage the solder ball due to heavy collision.

[0016]

Next, a method for aligning solder balls according to the present invention will be described in detail with reference to the accompanying drawings.

1 (a) to 1 (d) are cross-sectional views for explaining steps of an embodiment of a method of arranging solder balls according to the present invention. In FIG.
Reference numeral 2 denotes a solder ball serving as an external connection terminal of the package for housing a semiconductor element.

First, as shown in FIG. 1A, a solder ball alignment plate 1 for aligning solder balls 2 is prepared.

The solder ball alignment plate 1 is made of a hard resin such as bakelite, a metal such as stainless steel, or a combination of these materials, and has an alignment region 3 in which the solder balls 2 are aligned in the center of the upper surface thereof. At the outer periphery of the upper surface, a frame 4
have.

In the alignment region 3 of the solder ball alignment plate 1, concave portions 5 having suction holes 5a on the bottom surface are formed in a predetermined lattice arrangement.

The recess 5 has a size capable of accommodating the solder balls 2 therein one by one, more specifically, a diameter that is about 0.1 mm larger than the diameter of the solder ball 2 and has a depth about the same as the radius of the solder ball 2. The suction hole 5a having a diameter smaller than the diameter of the solder ball 2 is provided on the bottom surface thereof, and the air is accommodated in the recess 5 by sucking air downward from the suction hole 5a. It is possible to hold the solder ball 2 by suction.

The frame portion 4 is erected on the outer peripheral portion of the solder ball alignment plate 1 at a height of about 2 to 5 cm from the upper surface of the alignment region 3, and is placed on the solder ball alignment plate 1 as described later. When the solder ball 2 is inserted and the solder ball aligning plate 1 is swung, the solder ball 2 prevents the solder ball 2 from spilling out of the solder ball aligning plate 1 to the outside.

Next, as shown in FIG. 1B, a suitable number of solder balls 2 are put on the solder ball alignment plate 1. At this time, the number of the solder balls 2 to be charged is preferably about 5 to 50 times the number of the concave portions 5 formed in the solder ball alignment plate 1. If the number of the solder balls 2 to be supplied is less than five times the number of the concave portions 5, the solder ball aligning plate 1 is drawn while sucking air downward from the suction holes 5a of the concave portions 5 as described later.
When the solder balls 2 are adsorbed in the recesses 5 by swinging the solder balls 2, the distribution of the solder balls 2 on the solder ball alignment plate 1 becomes too sparse, and the solder balls 2 are efficiently placed one by one in the recesses 5. Tends to be unable to be adsorbed, and
If it exceeds 50 times, the distribution of the solder balls 2 on the solder ball alignment plate 1 becomes too dense, and the movement of the solder balls 2 is greatly suppressed. Adsorption tends to be difficult.

Next, as shown in FIG. 1 (c), air is drawn downward at a pressure of about 400 to 600 mmHg from a suction hole 5a provided on the bottom surface of the concave portion 5 of the solder ball alignment plate 1 by a suction device (not shown). While sucking, solder ball alignment plate 1
The solder ball 2 is attracted to each recess 5 of the solder ball alignment plate 1 by swinging once or twice at an angle of 30 to 60 ° and a cycle of 2 to 5 seconds / time.

In this case, since the solder ball 2 only rolls on the solder ball alignment plate 1 by the swing of the solder ball alignment plate 1, the solder ball 2 and the solder ball alignment plate 1 or the solder balls 2 collide violently. Thus, no scratches or dents occur in the solder ball 2. Therefore, when the solder balls 2 are welded to the connection pads provided on the bottom surface of the insulating container of the semiconductor device housing package, air is not entrapped between the connection pads and the solder balls 2 due to scratches or dents. In addition, the external connection terminals made of the solder balls 2 can be firmly attached to the connection pads.

At this time, some of the recesses 5 have 2
~ 3 solder balls 2 may be adsorbed simultaneously,
When two or three solder balls 2 are sucked into one recess 5, two or three solder balls 2 are arranged side by side on one recess 5 so as to close the recess. Is in a state where the solder ball 2 is not accommodated.

Therefore, as shown in FIG.
Air is sprayed onto the solder ball alignment plate 1 from the angle of about 20 to 40 ° at a pressure of 2 to 5 atmospheres for about 0.5 to 2 seconds from the angle of about 20 to 40 ° to the alignment area 3 by an air blowing nozzle 6 of about 0.5 to 2 mm. The excess solder balls 2 are removed, and one solder ball 2 is accommodated in each recess 5.

In this case, two or three solder balls 2
Are sucked at the same time, in the recess 5, the balance of the suction of the solder ball 2 is lost by blowing air,
Only one of them will be accommodated in the recess 5.

It should be noted that the angle, pressure, time, etc. of the air blowing may be determined appropriately within the above-described range according to the size and number of the solder balls 2.

Thus, according to the method of arranging solder balls of the present invention, the solder balls 2 are arranged in a predetermined grid-like arrangement in the alignment area 3 of the solder ball alignment plate 1 without causing scratches or dents in the solder balls 2. Can be easily aligned.

[0031]

According to the solder ball alignment method of the present invention,
After the solder ball aligning plate is swung to adsorb the solder balls into the concave portions formed in a predetermined arrangement, air is blown onto the solder ball aligning plate to remove excess solder balls. Even if a plurality of solder balls are adsorbed at the same time, the air is blown to blow the air out of balance of the plurality of solder balls adsorbed in one recess, and only one of them is accommodated in the recess. Therefore, solder balls can be accommodated one by one in all the concave portions, and the solder balls can be easily arranged in a predetermined lattice-like arrangement.

According to the solder ball alignment method of the present invention, since the solder balls are aligned by swinging the solder ball alignment plate, they only roll on the solder ball alignment plate. The solder ball alignment plate or the solder balls do not violently collide with each other and do not cause scratches or dents which may cause a problem in the welding step on the solder balls. Therefore, when a solder ball is welded as an external connection terminal to a connection pad provided on the lower surface of the insulating container of the semiconductor element storage package, air is trapped between the connection pad and the solder ball due to a scratch or a dent. Therefore, the external connection terminals made of solder balls can be firmly attached to the connection pads of the insulating container.

As described above, according to the present invention, all the recesses provided in the solder ball alignment plate can accommodate one solder ball at a time, and can easily align the solder balls in a predetermined arrangement. A method of aligning solder balls without causing scratches or dents in the solder balls can be provided.

[Brief description of the drawings]

1 (a) to 1 (d) are cross-sectional views for explaining steps of an embodiment of a method for aligning solder balls according to the present invention.

FIG. 2 is a cross-sectional view showing a ball grid array type semiconductor element housing package to which external connection terminals made of solder balls are attached.

FIG. 3 is a cross-sectional view for explaining a conventional solder ball alignment method.

FIG. 4 is an enlarged sectional view of a main part in the solder ball alignment method shown in FIG. 3;

FIG. 5 is a cross-sectional view for explaining another conventional solder ball alignment method.

[Explanation of symbols]

 1 ··· Solder ball alignment plate 2 ··· Solder ball 3 ··· Alignment area 5 ··· Depression 5a ··· Suction hole

Claims (1)

[Claims] 1. A solder ball alignment plate capable of accommodating one by one a solder ball to be an external connection terminal of a package for accommodating a semiconductor element, and having a plurality of concave portions having suction holes on a bottom surface arranged in a predetermined arrangement. Put a large number of the solder balls on the top, then swing the solder ball alignment plate while sucking air from the suction holes to adsorb the solder balls one by one in the recess, and then, A method of arranging solder balls, comprising blowing air onto the solder ball alignment plate, removing excess solder balls, and aligning the solder balls with the solder ball alignment plate.